Study of Dynamic Analysis Model on Subway Vehicle-Tunnel Vertical Coupled System

2012 ◽  
Vol 170-173 ◽  
pp. 1497-1503
Author(s):  
Bo Liang ◽  
Hong Luo ◽  
Wei Qing
Keyword(s):  
Dynamic Analysis ◽  
Coupled System ◽  
Coupling Model ◽  
Vertical Vibration ◽  
The Body ◽  
Analysis Model ◽  
Vibration Equation ◽  
Vibration Model ◽  
Dynamic Coupling Model ◽  
Tunnel System

In this paper, vehicle systems and track-tunnel system are regarded as an interactional, mutual coupling overall system and the interaction between wheel and rail is regarded as the “ligament” of these two subsystems. The vehicle vibration model and vibration equation are established by considering the body vertical vibration, a suspension of vertical vibration and wheelset vertical vibration. By the displacement compatibility condition of the vehicle and track, integrating the vehicle equations and discretized track-tunnel vibration equation, the dynamic coupling model and the equations that reflect the vehicle-track systematicness is constituted. It provides a reference for the further research of the dynamic analysis of vehicle-tunnel coupled system.

Dynamic Analysis of Cage Stress in Tapered Roller Bearings Using Component-Mode-Synthesis Method

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Tomoya Sakaguchi ◽  
Kazuyoshi Harada
Keyword(s):  
Rigid Body ◽  
Dynamic Analysis ◽  
Boundary Point ◽  
Axial Load ◽  
Synthesis Method ◽  
Load Condition ◽  
Component Mode Synthesis ◽  
Analysis Model ◽  
Tapered Roller ◽  
Tapered Roller Bearings

In order to investigate cage stress in tapered roller bearings, a dynamic analysis tool considering both the six degrees of freedom of motion of the rollers and cage and the elastic deformation of the cage was developed. Cage elastic deformation is equipped using a component-mode-synthesis (CMS) method. Contact forces on the elastically deforming surfaces of the cage pocket are calculated at all node points of finite-elements on it. The location and pattern of the boundary points required for the component-mode-synthesis method were examined by comparing cage stresses in a static condition of pocket forces and constraints calculated by using the finite-element and the CMS methods. These results indicated that one boundary point lying at the center on each bar is appropriate for the effective dynamic analysis model focusing on the cage stress, especially at the pocket corners of the cages, which are actually broken. A behavior measurement of a polyamide cage in a tapered roller bearing was conducted for validating the analysis model. It was confirmed in both the experiment and analysis that the cage whirled under a large axial load condition and the cage center oscillated in a small amplitude under a small axial load condition. In the analysis, the authors discussed the four models including elastic bodies having a normal eigenmode of 0, 8 or 22, and rigid-body. There were small differences among the cage center loci of the four models. These two cages having normal eigenmodes of 0 and rigid-body whirled with imperceptible fluctuations. At least approximately 8 normal eigenmodes of cages should be introduced to conduct a more accurate dynamic analysis although the effect of the number of normal eigenmodes on the stresses at the pocket corners was insignificant. From the above, it was concluded to be appropriate to introduce one boundary point lying at the center on each pocket bar of cages and approximately 8 normal eigenmodes to effectively introduce the cage elastic deformations into a dynamic analysis model.

scholarly journals Sensitivity analysis on a dynamic coupling model for V2V communication distance control

2021 ◽  
Vol 184 ◽  
pp. 372-379
Author(s):  
Darko Frtunik ◽  
Amolika Sinha ◽  
Hanna Grzybowska ◽  
Navreet Virdi ◽  
S. Travis Waller ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Coupling Model ◽  
Dynamic Coupling ◽  
V2v Communication ◽  
Distance Control ◽  
Communication Distance ◽  
Dynamic Coupling Model

scholarly journals Dynamic Modeling and Anti-Disturbing Control of an Electromagnetic MEMS Torsional Micromirror Considering External Vibrations in Vehicular LiDAR

Micromachines ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 69
Author(s):  
Yong Hua ◽  
Shuangyuan Wang ◽  
Bingchu Li ◽  
Guozhen Bai ◽  
Pengju Zhang
Keyword(s):  
Dynamic Model ◽  
Optical Switching ◽  
Control Method ◽  
Sliding Mode ◽  
Algorithm Design ◽  
Coupling Model ◽  
Micro Electro Mechanical Systems ◽  
Mems Technology ◽  
Torsional Micromirror ◽  
Dynamic Coupling Model

Micromirrors based on micro-electro-mechanical systems (MEMS) technology are widely employed in different areas, such as optical switching and medical scan imaging. As the key component of MEMS LiDAR, electromagnetic MEMS torsional micromirrors have the advantages of small size, a simple structure, and low energy consumption. However, MEMS micromirrors face severe disturbances due to vehicular vibrations in realistic use situations. The paper deals with the precise motion control of MEMS micromirrors, considering external vibration. A dynamic model of MEMS micromirrors, considering the coupling between vibration and torsion, is proposed. The coefficients in the dynamic model were identified using the experimental method. A feedforward sliding mode control method (FSMC) is proposed in this paper. By establishing the dynamic coupling model of electromagnetic MEMS torsional micromirrors, the proposed FSMC is evaluated considering external vibrations, and compared with conventional proportion-integral-derivative (PID) controls in terms of robustness and accuracy. The simulation experiment results indicate that the FSMC controller has certain advantages over a PID controller. This paper revealed the coupling dynamic of MEMS micromirrors, which could be used for a dynamic analysis and a control algorithm design for MEMS micromirrors.

Experimental study on vertical vibration characteristics of medium-low speed maglev vehicle when standing still on steel beams

2021 ◽  
pp. 095440972110324
Author(s):  
Miao Li ◽  
Xiaohao Chen ◽  
Shihui Luo ◽  
Weihua Ma ◽  
Cheng Lei ◽  
...  
Keyword(s):  
Coupled System ◽  
Vertical Vibration ◽  
Vibration Characteristics ◽  
Steel Beams ◽  
Steel Beam ◽  
Air Spring ◽  
Low Speed ◽  
Maglev Vehicle ◽  
Excited Vibration ◽  
Eigen Frequencies

Levitation stability is the very basis for the dynamic operation of Electromagnetic Suspension (EMS) medium-low speed maglev trains (MSMT). However, self-excited vibration tends to occur when the vehicle is standing still above the lightweight lines, which remains a major constraint to the promotion of medium-low speed maglev technology. In order to study the vertical vibration characteristics of the coupled system of MSMT when it is standing still above lightweight lines, levitation tests were carried out on two types of steel beams: steel beam and active girder of the turnout, with a newly developed maglev vehicle using levitation frames with mid-set air spring. Firstly, modal tests were carried out on the steel beam to determine its natural vibration characteristics; secondly, the acceleration signals and the dynamic displacement signals of the air spring obtained at each measurement point were analyzed in detail in both the time and frequency domains, and the vertical ride comfort was assessed by means of the calculated Sperling index. Subsequently, theoretical explanations were given for the occurrence of self-excited vibration of coupled system from the perspective of the vehicle-to-guideway vibration energy input. Results show that the eigen frequencies of the vehicle on the steel beam and the turnout are 9.65 Hz and 2.15 Hz, respectively, the former being close to the natural frequency of the steel beam while the latter being close to the natural frequency of the air spring suspension system, thus causing the self-excited vibration of the coupled system. It is recommended to either avoid the main eigen frequencies of the coupled system or to increase the damping of the corresponding vibration modes to guarantee a reliable coupled system for its long-term performance. These results may provide valuable references for the optimal design of medium-low speed maglev systems.

Android Botnets

2021 ◽  
pp. 75-92
Author(s):  
Ahmad Karim ◽  
Victor Chang ◽  
Ahmad Firdaus
Keyword(s):  
Dynamic Analysis ◽  
High Accuracy ◽  
Remote Access ◽  
Learning Approaches ◽  
Analysis Model ◽  
Hybrid Analysis ◽  
Static And Dynamic Analysis ◽  
Mobile Botnet ◽  
Wide Scale ◽  
Access Information

Mobile botnets are gaining popularity with the expressive demand of smartphone technologies. Similarly, the majority of mobile botnets are built on a popular open source OS, e.g., Android. A mobile botnet is a network of interconnected smartphone devices intended to expand malicious activities, for example; spam generation, remote access, information theft, etc., on a wide scale. To avoid this growing hazard, various approaches are proposed to detect, highlight and mark mobile malware applications using either static or dynamic analysis. However, few approaches in the literature are discussing mobile botnet in particular. In this article, the authors have proposed a hybrid analysis framework combining static and dynamic analysis as a proof of concept, to highlight and confirm botnet phenomena in Android-based mobile applications. The validation results affirm that machine learning approaches can classify the hybrid analysis model with high accuracy rate (98%) than classifying static or dynamic individually.

The Dynamic Response of Zhengyangmen Gate Tower Induced by Beijing Metro Line 2

2014 ◽  
Vol 580-583 ◽  
pp. 1212-1217
Author(s):  
Qi Song ◽  
Jia Qi Guo ◽  
Wen Hua Chen ◽  
Ping Guo
Keyword(s):  
Dynamic Response ◽  
Dynamic Analysis ◽  
Test Data ◽  
Vibration Test ◽  
Analysis Model ◽  
Response Characteristics ◽  
The North ◽  
Cultural Relic ◽  
Dynamic Response Characteristics ◽  
South Axis

Zhengyangmen gate tower is a national emphasis cultural relic unit along the north-south axis of Beijing, which is above the Beijing metro line 2. Based on dynamic analysis model of gate tower and the position of gate tower and subway, the dynamic response characteristics of gate tower induced by Beijing metro line 2 are calculated, and compared with the in-site vibration test data.

Dynamic Analysis of Bridge-Approach Embankment Transition Segment

2012 ◽  
Vol 238 ◽  
pp. 719-722
Author(s):  
Zhen Xia Li ◽  
Yuan Zhao Chen
Keyword(s):  
Dynamic Analysis ◽  
Coupled System ◽  
Dynamic Responses ◽  
Subgrade Reaction ◽  
Track Dynamics ◽  
Bridge Approach

Dynamic responses of coupled system were analyzed when the speed of train was 350km/h and the transition was filled with graded broken stones mixed 5% cement. Results indicate that setting form of bridge-approach embankment section has little effect on dynamic responses, thus designers can choose it on account of practical circumstances. Based on the study from vehicle-track dynamics, we suggest that the coefficient of subgrade reaction (K30) should be greater than 190MPa within 0-5m zone behind abutment and be greater than 150MPa in other zones.

Dynamic Analysis of a Motion Transformer Mimicking a Hula Hoop

2009 ◽  
Author(s):  
C. X. Lu ◽  
C. C. Wang ◽  
C. K. Sung ◽  
Paul C. P. Chao
Keyword(s):  
Dynamic Analysis ◽  
Homotopy Perturbation Method ◽  
The Body ◽  
Energy Scavenging ◽  
Electric Circuits ◽  
Main Mass ◽  
Transformer Design ◽  
Varied System ◽  
Steady State Solutions ◽  
Lagrange’S Method

Hula-hoop motion refers to the spinning of a ring around a human body; it is made possible by the interactive force between the moving ring and the body. Inspired by the generic concept of hula-hoop motion, this study proposes a novel motion transformer design that consists of a main mass sprung in one translational direction and a free-moving mass attached at one end of a rod, the other end of which is hinged onto the center of the main mass. It is expected that the transformer is capable of transforming linear reciprocating motion into rotational motion. In addition, the transformer could be integrated with coils, magnets, and electric circuits to form a portable energy scavenging device. A thorough dynamic analysis of the proposed transformer system is conducted in this study in order to characterize the relationships between the varied system parameters and the chance of hula-hoop motion occurrence. The governing equations are first derived by using Lagrange’s Method, which is followed by the search for steady-state solutions and the corresponding stability analysis via the homotopy perturbation method and Floquet theory. Direct numerical simulation is simultaneously performed to verify the correctness of the approximate analysis. In this manner, the feasibility of the proposed design and the occurrence criteria of hula-hoop motion are assessed.

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